Efficacy of tailored Helicobacter pylori eradication therapy based on antibiotic susceptibility and CYP2C19 genotype

Table 1 Major factors preventing eradication of Helicobacter pylori infection

	Factor
Antibiotics	Resistance to antibiotics	Clarithromycin
		Metronidazole
		Levofloxacin
		Amoxicillin
Inhibition of acid secretion	CYP2C19	Rapid metabolizer
	CYP2C19*17	*17 carrier
	ABCB1 3435	C/C genotype (Caucasian)
	IL-1B-511	C/C genotype
	IL-1B-31	T/T genotype
	Acid inhibitory drug dosing time	Low frequency (oid)
	Acid inhibitory drug dosing dose	Insufficient dose
H. pylori phenotype	H. pylori virulence factors	cagA-negative
		vacA s2 genotype
Environment	Volume	Much
	Smoking	Many
	Compliance	Poor

CYP2C19: Cytochrome P450 2C19; IL: Interleukin; ABCB1: Multidrug resistance protein-1; H. pylori: Helicobacter pylori.